1. Field of the Invention
The present invention relates to piling and pile driving and more particularly relates to an improved composite timber and concrete pile construction. Even more particularly, the present invention relates to an improved method for installing composite pile constructions which include a lowermost timber pile section and an uppermost concrete pile section wherein the timber pile section is first driven below the earth's surface a distance, leaving a small portion exposed. A hollow steel, tubular sleeve is partially filled with concrete and allowed to set. The concrete pile and steel tube is then joined to the top of the timber pile. The unfilled portion of the steel tubular sleeve defines a connector that is embedded in the top of the timber pile. The assembly is then driven into the ground.
2. General Background
In various areas of the country where bearing pressures of soil are low and/or unsuitable for building purposes, construction can employ the use of one or more elongated load carrying elements referred to in the industry as a pile or piling. These devices for transferring load between a building and the underlying earth can be concrete, steel, or timber, in construction.
Timber piling are usually somewhat restricted in length because of the very nature of their source, namely trees. Thus it is desirable to splice piling together to form piling of extended length. These timber pilings can also vary in diameter from end to end, complicating the splicing operation. Timber piling above the water line is generally more prone to rotting. Thus, it is desirable to use a concrete pile above the water line when composite piling are used.
Often times timber pile are combined with piling of other construction such as, for example, concrete. U.S. Pat. No. 3,003,323 issued to A. R. Holt provides a "Composite Pile Connector." A "Pile Splicer" is also the subject of U.S. Pat. No. 3,802,206 issued to Robert Moore, et al. In the patent a splicing means for connecting two wood piles end to end to make a long pile for the transfer of pile loads to a lower stronger ground is disclosed. The splicer in that patent provides a plate-like, substantially horizontal element adapted to lie between adjacent pile ends. Optional epoxy glue between the upper and lower surfaces can be provided between the element and the upper and lower piles. A central upright dowel member extends above and below the plate-like element driven into each pile element respectively. The Moore patent contemplates a driving of the entire pile assembly after splicing. This is unlike the present invention where the second pile section is added after the first lowermost pile section is already driven to its final position.
A "Composite Pile and Method of manufacture" is the subject of U.S. Pat. No. 4,252,473 issued to Albert M. Thomas, et al. The composite section includes a wooden section and a helically corrugated shell secured to the wooden section by a transition fitting. The corrugated steel carries a splice element that connects with the timber pile section. After driving, a liquid slurry of unhardened concrete can be added to the bore of the corrugated shell. Thus, the shell acts as a form for the concrete. A composite concrete and timber pile is the subject of U.S. Pat. No. 1,471,124 entitled "Means of connecting Ferro or Reinforced Concrete Piles to Wooden Piles." "Composite Piles and Joiners Therefore" is the subject of U.S. Pat. No. 2,912,829 issued to W. H. Cobi. The Cobi patent shows a composite concrete and timber pile with a splice element therefore.
A "Method and Apparatus for splicing Replacement Pile Sections to a Pile Stub" is the subject of U.S. Pat. No. 3,720,068 issued to E. r. DeRosa. That patent, however, deals with metal pile sections which are repaired with another metal pile section.
A splice element for two wooden utility poles, for example, is provided in U.S. Pat. No. 4,032,244. The extension would be attached to the flatten top of an existing pole. A projecting center shaft extends for the bracket to be received within mating center bores provided in the utility pole, a wooden extension pole or both. Threaded fasteners and metal straps complete the interconnection between the existing pole and the extension pole.
A "Pile Coupling and a Method of Pile Driving" is seen in U.S. Pat. No. 3,762,173 issued to Richard Marsh. The patent discloses a means for coupling sections of pile and a method of driving pile utilizing a thin-wall composite pile section. the coupling comprises a thin-wall sleeve with a telescoping thick-wall rings or collar mechanically anchored within the sleeve. Taps integrally formed in the collar, or the entire collar itself, are expanded within the sleeve to form correspondingly anchor pots in the sleeve thereby mechanically interlocking the collar and sleeve. The coupling is adapted for use in coupling successive sections of thick-wall tubular pile or in coupling thin-wall tubular composite pile or thick-wall tubular pile. Use of the thin-wall tubular composite pile enables employment of a method for driving which eliminates the necessity for retaining a succeeding thick-wall tubular pile after the initial one is driven home.
U.S. Pat. No. 3,003,323 issued to A. R. Holt entitled "Composite Pile Connector" shows a connector for use with a lower second of wood and an upper section of metallic pipe as part of a composite pile assembly. the connector includes a metallic ring having two plates disposed as chords within the ring, each chordal plate meeting at one end with the other so as to form the apex of a V with one leg on each side of the center of the ring. The plates are welded to the ring and the plates are of a length greater than the radius of the rings. The plates serve to displace the wood of a wood pile so as to wedge it tightly within the ring. This is unlike the present invention which uses a precast, hardened reinforced concrete pile as the upper pile section and joins that section to a lowermost timber pile section as part of a composite pile structure.
Daigle et al., U.S. Pat. No. 4,547,096 entitled "Alignment of Tubular Piles for Joinder," provides a method of alignment for two tubular piles. The aligner extends from one end of the tubular pile for insertion into the other tubular pile. One or more shim members are disposed between and in engagement with the outer surface of the aligner extended portion and the inner surface of the outer tubular pile when the extended portion is inserted therein for maintaining the tow piles in alignment for joinder. This patent differs from the present invention because it does not contemplate the joining of a reinforced concrete and timber pile as part of a composite section.
Applicant also is the patentee of a prior U.S. Pat. No. 4,431,347 issued Feb. 14, 1984, and entitled "Composite Timber Pile System". In that prior Gillen patent, a method of driving composite timber pile sections provides a pair of timber pile sections, the first of which is driven into the earth a distance leaving the butt of the pile exposed. A splice element is embedded into the remaining pile section and leveling material is added to the top of the first pile section.
Applicant's prior U.S. Pat. No. 4,525,102 entitled "Timber Pile Connection System" provides a method of driving composite timber pile sections which provides a pair of timber pile sections, the first of which is driven into the earth a distance leaving the butt of the pile exposed. A splice element is embedded into the remaining pile section and leveling material is added to the top of the first pile section. Upon assembly and during driving, the leveling material is laterally confined with the splice element while the respective mating surfaces of the two pile sections confine the leveling material vertically with the leveling material thus transferring compressive forces between the two pile sections. The splice element is a cylindrical element having a hollow bore which during operation contains the leveling material. The prior Gillen patent differs from the present invention in that it contemplates a driving of the composite pile section. further, the first timber pile section is driven a distance downwardly, but leaving the butt portion of the pile exposed so that the splice element and leveling material can be added. This is unlike the present invention wherein the lowermost pile section is driven well below the earth's surface, and in fact a distance substantially equal to the length of the second pile section which is of reinforced concrete rather than timber.
A method of driving composite piles is seen in the Ingalls U.S. Pat. No. 4,102,141. In that patent, a composite pile structure is formed from a lower wooden section and an upper tubular metal section which is connected to the wood member and then filled with concrete. The wooden section is first started into the ground a desired distance and the metal section is then supported by the upper end of the wooden member. A mandrel member is located in driving engagement with the upper end of the metal section and the lower end of the mandrel is supported in space relation to the wooden member. Initial hammer energy of limited intensity is applied to drive the metal section into the wooden member until the bottom of the mandrel comes into contact with the top of the wooden member. Thereafter, hammer energy of greater intensity is applied to the connected sections and concentrated against the surface of the wooden member enclosed by the embedded metal section. The method contemplates liquid slurried concrete to be added to the metal section after the composite pile is driven to the desired depth. This is unlike the present invention wherein a precast, hardened reinforced concrete pile section is connected to the lowermost timber pile section after the lowermost timber pile section is driven fully to its elevational position, usually well below the surface.